We train for hours on end. We get massages, eat carefully, visit doctors, acupuncturists, and even witch doctors - anything that we feel might enhance our performance in our chosen sport. But one missing component may be smiling at you in the mirror.

In 2012, the British Journal of Sports Medicine surveyed nearly 300 Olympic athletes and found that more than half of them had, to put it bluntly, bad teeth.  Fifty-five percent of athletes reported cavities, 45% reported dental erosion, and 76% reported gingivitis. This wouldn't be too big of a problem except that over 40% of the athletes said they were "bothered" by their oral health, 28% reported an impact on quality of life, and 18% reported an impact on training and performance.  To summarize: Nearly one in every five athletes surveyed said poor oral health had a negative impact on their athletic goals. 

Other studies (such as this one, published in the Scandinavian Journal of Medicine & Science in Sports in 2014) have also documented a link between high-performing athletes and bad teeth. Specifically, the 2014 study found that training volume correlated to the prevalence of cavities. The authors also found that endurance athletes were at an overall "higher risk" for dental erosion than their sedentary counterparts. 

So what is causing this poor oral health in athletes?  One theory is that high consumption of sugary sports drinks and gels eats away at enamel, leading to tooth decay.  In 2011, the International Journal of Sports Medicine published a study that examined the eating habits of triathletes. A large majority (84%) of participants said they sip on sports drinks while training, and almost 94% said they eat while training. The authors concluded that this diet (replete with sports drinks, sugary foods, and gels) is "consistent with a high risk profile" for cavities and tooth decay. While the study cautioned against generalizing the results too much due to a small sample size (only 31 triathletes), how many of us would agree that those eating and drinking habits sound familiar?

Other studies, however, have not found a strong link between sports drink consumption and cavities.  For example, a 2002 study published in Caries Research found that among 304 collegiate athletes, the volume and frequency sports drink consumption had no relationship to tooth decay. An earlier 1997 study published in the British Dental Journal arrived at the same conclusion after examining 55 cyclists and swimmers. Another 2002 study (this one from the Australian Dental Journal) also found no relationship between sports drink consumption and tooth decay.  This seeming lack of a relationship between sports drinks and cavities is likely why the American Journal of Dentistry concluded in a 2005 literature review "other factors such as… salivary production may be more important determinants of dental erosion [than consumption of sports drinks]."

Since then, other researchers have explored reduced saliva production as a cause for poor oral health in athletes. In 2008, a Scandinavian journal published a study that linked exercise and decreased saliva production. Scientists found that during physical exertion, the water content of participants' saliva decreased, and levels of cortisol increased. Saliva contains proteins that counteract tooth-eating bacteria, and it plays an important role in maintaining a healthy pH balance in the mouth. This is why acidic foods, including soda, which alter oral pH values, have been linked to tooth decay. Lower saliva levels, therefore, are detrimental to healthy teeth. Fortunately for most participants, altered saliva production rates returned to normal a few hours after exercise. However, researchers found that for athletes who exercised for several hours a day for many months (again… sound familiar?), saliva composition was permanently altered. The study also noted that heavier breathing tends to dry out the mouth, which is also detrimental to oral health. 

This link between low salivary production and oral health was further emphasized in a 2012 study published in BMC Oral Health. Researchers divided 18-32 year olds into two groups: those who exercised hard at least twice a week, and those who did not. Prevalence of "dental erosive wear" was 44% higher in the exercising group than in the sedentary group. Also, participants with higher reductions in saliva production (relative to other exercisers) during exercise were found to be more likely (again, relative to other exercisers) to experience dental erosive wear – further indicating a link between low saliva rates and tooth decay. 

Lastly, the 2014 Scandinavian Journal of Medicine & Science in Sports study mentioned above also helps to strengthen the relationship between heavy exercise and tooth decay. Researchers compared 35 triathletes with non-triathletes and found that the triathletes showed an increased risk for dental erosion. Specifically, researchers noted that during exercise, athletes showed reduced saliva rates and increases in saliva pH, which they concluded were likely contributors to the dental decay. (There was no significant difference between saliva rates and pH levels of triathletes and controls when the participants were sedentary.) 

What's behind the relationship between exercise and reduced saliva rates? 

In a word: dehydration. Not only are saliva rates accurate predictors of dehydration (Medicine & Science in Sports & Exercise, 2004), scientists have also found that lower saliva rates caused by dehydration do not return to normal even 24 hours after rehydration (Journal of Gerontology, 1997). This inability to quickly restore healthy saliva rates may be one of the reasons athletes who exercise for several hours a day experience permanent changes in saliva production (as mentioned above in the 2008 Scandinavian study). 

"We had thought sports drinks and nutrition might have the most detrimental influence on dental decay," Dr. Cornelia Frese, a lead research behind the 2014 Scandinavian Journal of Medicine & Science in Sports study, told The New York Times. But after finding no links between dietary habits and oral health, she said researchers instead focused on saliva production. Since saliva "has a very protective function for teeth, having less of it or a chemically different version during exercise could be problematic," she said. While Dr. Frese wouldn't commit to generalizing the results to people who exercise fewer than nine hours per week, she does say that based on the data from this group, "prolonged endurance training might be a risk factor for oral health." 

To put it more plainly, if you're training for an Ironman, you had better pay attention to your teeth. 

Poor oral health and performance: Why all of this matters.

Is there a proven relationship between poor oral health and reduced performance? You bet. In fact, tooth decay has been linked to decreased performance in everything from academics to sex. Also, as stated above, nearly one in five 2012 Olympic athletes surveyed reported that their bad teeth negatively affected their ability to train. A similar survey of Olympic athletes (1992, International Dental Journal) found that 8% of athletes thought that oral problems disturbed their training and 5% thought it affected their sporting performance. 

This decrease in athletic performance is likely caused by three things:

Pain: In a 2011 study published in Dental Traumatology, 66% of Brazilian basketball players surveyed reported that oral problems could "diminish their strength" during training and performance. They also expressed hesitation toward resuming time on the court after oral trauma. 

As Ian Needleman, lead researcher behind the London Olympics survey, told Medical News Today, "Pain and discomfort from tooth decay, dental erosion, [gum] disease, or infected wisdom teeth will affect performance. We see psychological impacts from, for example, bleeding gums, bad odors and poor appearance."

Inflammation: A 2011 study, published in Oral Medicine, found a correlation between poor oral health and proneness to injury (measured by the number of intrinsic injuries, i.e., muscle, ligament/tendon or bone) in Spanish soccer players.

The medical community has postulated (2010, Journal of Indian Society of Periodontology) that tooth decay leads to inflammation as the body attempts to fight the bacterial overgrowth that causes cavities. Athletes put their bodies under tremendous amounts of stress, so anything that hampers the body's ability to recover can become an impediment. Thus, the inflammatory response from tooth decay likely leaves athletes susceptible to injury in other areas of the body.

Again, Needleman explains, "Infection in the mouth… increases the levels of inflammation in the rest of the body, and this can impair performance as well as increase risk of injury." 

Lowered confidence: Lastly, poor oral health has been linked (1988, Community Dental Health) to decreased social confidence and lower quality of life. As most endurance athletes know, it takes a high level of confidence and social support to succeed. It is easy to see why impaired self-esteem and interpersonal relationships could negatively affect sports performance. 

What are the strategies for good oral health?

Preventing poor oral health is actually pretty straightforward. This is one case in which the advice your parents gave you growing up is just as true today.

Stay properly hydrated: Dr. Frese said she tells athletes to stay hydrated to mitigate the potentially negative effects of decreased saliva production. Drinking water and consuming adequate levels of electrolytes is important in maintaining healthy saliva rates. And because dehydration can impair saliva production for up to 24 hours, it is all the more important to maintain adequate fluid levels in the first place. 

Go to the dentist: It may seem obvious, but nearly half of the athletes surveyed at the London Olympics had not undergone a single dental exam in the previous year. You could even consider visiting a dentist with a specialty in sports dentistry, Dr. Frese said. 

Stay aware: Lastly, take daily steps to examine your oral health. These include brushing your teeth, flossing, and paying attention to any pain that occurs when eating. If you think you may have a problem, get it checked out sooner rather than later. As 18% of the London Olympic athletes will likely tell you, it is better to do it now than to wait until it impairs your training. 

Conclusion:

"Oral health could be an easy win for athletes, as the oral conditions that can affect performance are all easily preventable," Needleman told the Huffington Post. "Simple strategies to prevent oral health problems can offer marginal performance gains that require little or no additional time or money."


Jonathan Toker is a Canadian elite-level runner and triathlete. He received a Ph.D. in organic chemistry from The Scripps Research Institute in 2001, raced in the professional ranks as a triathlete for 5 years, and now mostly runs on trails. Dr. Toker worked as a scientist in the biotech industry for 5 years prior to launching his unique SaltStick Electrolyte Capsule and Dispenser lineup.